merantix-momentum/squirrel-core: v0.12.3

What's Changed Update README.md by @ThomasWollmann in https://github.com/merantix-momentum/squirrel-core/pull/31 pin numpy and update PR template by @TiansuYu in https://github.com/merantix-momentum/squirrel-core/pull/34 Update README.md by @ThomasWollmann in https://github.com/merantix-momentum/squirrel-core/pull/33 update document links by @TiansuYu in https://github.com/merantix-momentum/squirrel-core/pull/36 update version to 0.12.3 by @TiansuYu in https://github.com/merantix-momentum/squirrel-core/pull/37 Full Changelog: https://github.com/merantix-momentum/squirrel-core/compare/v0.12.2...v0.12.